Various types of anti-fog coatings are available in the marketplace, but they lack abrasion resistance or mechanical durability. Typically these anti-fog coatings are both readily abraded or easily dissolved in the cleaning solvents and substances used to clean such coated materials, such as isopropyl alcohol, bleach solutions, and other solvents. Commercially available, anti-scratch coatings, on the other hand, do not have any anti-fog properties. Hence, there is a demand for a more durable, permanent anti-fog coating and for such an anti-fog coating having anti-scratch properties and vice-versa in the marketplace.
Typically anti-fog coatings are formed using wet chemical application methods, such as, described in U.S. Pat. Nos. 4,029,842, 4,080,476, 4,467,073, 4,847,160, 5,075,133 and EP 460,382.
The production of anti,scratch or abrasion resistant coatings by processes employing plasma techniques and silicon containing compounds to provide inorganic coatings containing SiO.sub.1.5.-2.0 and/or silicon carbide (SIC) is known. For example, in U.S. Pat. No. 4,830,873 the resultant thick (6-8 microns), abrasion resistant coating contains SiO.sub.1.5-2.0, SiC and Si.sub.3 N.sub.4 ; in U.S. Pat. No. 4,927,704 an anti-scratch layer of SiO.sub.2 was deposited over a gradational layer, which in turn, was deposited over a plasma-polymerized vinyltrimethylsilane base layer; in U.S. Pat. No. 5,211,995 a layer of SiO.sub.2 is deposited using a silane (SiH.sub.4)/nitrous oxide (N.sub.2 O) system over a decorative, organic material layer; and in JP SHO 60-155675 a surface-hardened film layer containing SiC and silanol groups is deposited from gaseous mixtures of certain silicon-containing compounds. Co-pending application Ser. No. 08/230,025, titled "POLYMERIC ARTICLE WITH IMPROVED SURFACE PROPERTIES," inventors McPherson and Hozbor, filed Apr. 19, 1994, of common assignment herewith, describes a process for modifying the surface of a polymeric article with a low temperature plasma gas composition consisting essentially of a mixture from 80 to 40 mole percent N.sub.2 O and with 20 to 60 mole percent CO.sub.2, where such modified surface has improved adhesive strength to another similarly treated surface and improved receptivity for paint and other coatings.